ui/ncurses: Unify key bindings & key help text

This change is a small cleanup of the key bindings; we ensure that the
general key bindings are available (and documented) on all screens.

In order to keep things consistent, this change adds an initial UI
guidelines text file, which documents the general key bindings.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 44 insertions, 0 deletions

diff --git a/ui/ncurses/ui-guidelines.text b/ui/ncurses/ui-guidelines.text
new file mode 100644
index 0000000..c416fc7
--- /dev/null
+++ b/ui/ncurses/ui-guidelines.text
@@ -0,0 +1,44 @@
+Petitboot ncurses UI guidelines
+
+General key bindings:
+
+ x: Exit the current screen
+ 
+    When the focus is on a text-input field, this key will be treated
+    litereally (ie, it inputs an 'x' in to the text field). Because of this,
+    we should avoid putting a text field as the first field on a screen.
+
+    We also support 'Esc' as a secondary exit key, but this can cause
+    problems with some terminals (because Esc is used to initiate an input
+    escape sequence, it causes ncurses to delay, waiting for more keys).
+    So, Esc should not be listed as a key in the UI help.
+
+ h: Show help
+
+    Same restrictions as the 'x' key with text input widgets. We support F1
+    too, but this is often used by the actual terminal emulator to show help
+    locally instead.
+
+Form key bindings:
+
+ tab: Next widget
+ shift+tab: Previous widget
+
+ down: Next widget
+ up: Previous widget
+
+Text screen key bindings:
+
+ up/down: scroll
+
+Menu key bindings:
+
+ up: Next item
+ down: Previous item
+
+ tab: Next item
+ shift+tab: Previous item
+
+ Enter: select item
+ Space: select item
+